<div class="download-container">
    <div class="download-btn" onclick="downloadDoc()">
        点击下载操作手册
    </div>
</div>

<style>
    .download-container {
        position: fixed;
        right: 10px;
        bottom: 10px;
        width: 50%;
        height: 100px;
        background: slateblue;
        color: white;
        display: flex;
        justify-content: center;
        align-items: center;
        border-radius: 10px;
    }

    .download-btn {
        width: 50%;
        height: 50px;
        background: red;
        margin: 0 auto;
        border-radius: 10px;
        display: flex;
        justify-content: center;
        align-items: center;
        font-size: 25px;
        font-weight: bolder;
        cursor: pointer;
        user-select: none;
    }
</style>